This is why paying for dedicated memory is often more expensive than its counter part, because that dedicated memory is not considered as part of pooling.
Just because you can doesn't mean you should.
And then they learn all hotels are doing exactly same thing. One hotel doing is risk, all hotels doing is industry standard.
Airlines, hotels, restaurants, doctors and so on oversubscribe all the time. Whoever complains are free to move and add to their further disappointments.